My users often call me to say that the shared calendars they are using
have disappeared. I did the research, and apparently it can be a
corrupt navpane (which can be cured by running outlook.exe /
resetnavpane) or it can be a known bug with no solution:

http://cs.its.uiowa.edu/exchange/pro...listdisappears
wrote:
Periodically, the list of shared Calendars will disappear and these
Calendars will need to be reopened to rebuild the list. [...] Microsoft
has now stated as of 6/7/07 that there is a bug regarding shared
calendars disapperaing when users are in online mode.

In http://groups.google.com/group/micro...2e0b69ae24c7be
on Feb 11 2008, 7:38*pm, "Diane Poremsky" wrote:
I wasn't sure if you meant there or in group schedules. There is a known
issuewhere they don't stick well, especially if you lose connectivity to
the server. Try opening outlook using the /resetnavpane switch - if it
doesn't help, then it’s the bug. (Using this switch will delete all folder
shortcuts added to the navigation pane (including Favorite folders).)

...etc. We have a new Exchange 2007 environment (new AD and all new
servers, previously we weren't running Exchange or AD) and Outlook
2007 SP1.

Resetting the navpane obviously doesn't work (else I wouldn't post
this). Is there a hotfix for the bug?